I don't quite understand why we need three libraries for dealing with IP address blocks, but "choice" is a double-edged sword. This is the first one I stumbled upon and began using, and then after realizing that I had other options, did my research. I agree with this author, that it is probably more a matter of preference than anything else, but NetAddr::IP does seem to have the widest range of functionality.

So as my preferences go, GNU/Linux for os's, Debian for GNU/Linux distros, Perl for high-level programming, and now NetAddr::IP for IP Address Abstraction in Perl, I think we need the following added to the NetAddr suite:
NetAddr::MAC for MAC Addresses
NetAddr::OSI for OSI networks
NetAddr::IP::isMask validate string as a mask from any notation "contiguous 1's on the left followed by contiguous 0's to the right"